Dell SmartFabric OS10 User Guide Release 10.5.3

Parameter assignment based on Remote-ID option

In this scenario, there are two DHCPv6 relay agents that are connected to the VLT peers. The hosts that are connected to the two DHCPv6 relay agents belong to different VLANs that are part of different VRFs. The link address subnet in the DHCPv6 RELAY-FORWARD message from either of the DHCPv6 relay agents can be the same. The IPv6 address range and the configuration parameters for the hosts connected to different DHCPv6 relay agents are managed by the administrator based on the remote-ID option value in the DHCPv6 relay agent.

The remote identification is configured globally. By default, the DHCPv6 relay agent type 3 DUID (system mac) is used as the remote-ID value. You can optionally configure a customized string. In VLT cases, VLT MAC address is used to generate the DUID.

The prefix is an optional parameter to be configured globally. You can configure hostname, VRF Name, hostname, and VRF name or customized string as prefix. Optionally, you can configure DHCPv6 hostname.

The prefix and the remote identification are separated by the colon ( : ). For example, prefix : Remote Identification.

Following are the different formats of the remote-ID value with different configuration of the prefix.

Host name as prefix :
        <Host name> : <Remote identification>
        e.g.: DELL OS10:90b11cf4a65d

        VRF Name as prefix :
        <VRF Name of the interface> : <Remote identification>
        e.g.: RED:90b11cf4a65d

        Both Host name and VRF Name as prefix :
        <Host name>-<VRF Name of the interface> : <Remote identification>
        e.g.: DELL OS10-RED:90b11cf4a65d

CLI Configuration:

DHCPv6 Relay Agent 1:

Global config:
ipv6 dhcp-relay remote-id
ipv6 dhcp-relay prefix remote-id hostname vrfname
ipv6 dhcp-relay hostname DELL

Interface configuration:
OS10#show running-configuration
interface Ethernet 1/1/1
no shutdown
channel-group 10 mode active
!
interface port channel 10 
no shutdown
vlt portchannel 10
ip address 10.1.1.1/24
ip helper-address 20.1.1.2
Ip vrf forwarding red
!
interface Ethernet 1/1/2
no shutdown
ip address 20.1.1.1
!
ip vrf red
!

DHCPv6 Relay Agent 2:

Global config:
ipv6 dhcp-relay remote-id
ipv6 dhcp-relay prefix remote-id hostname vrfname
ipv6 dhcp-relay hostname DELL

Interface configuration:
OS10#show running-configuration
interface Ethernet 1/1/1
no shutdown
channel-group 10 mode active
!
interface port channel 10 
no shutdown
vlt portchannel 10
ip address 10.1.1.0/24
ip helper-address 20.1.1.2
ip vrf forwarding red
!
interface Ethernet 1/1/2
no shutdown
ip address 20.1.1.0
!
ip vrf red
!

DHCP Server

OS10(config)# ip dhcp server
OS10(config-dhcp)# pool dell_1
OS10(config-dhcp-dell_1)# network 10.1.1.0/24
OS10(config-dhcp-dell_1)# range 10.1.1.2 10.1.1.10
OS10(config-dhcp-dell_1)# default-router 10.1.1.1
OS10(config-dhcp-dell_1)# end

OS10(config-dhcp)# pool dell_2
OS10(config-dhcp-dell_2)# network 20.1.1.0/24
OS10(config-dhcp-dell_2)# range 20.1.1.2 20.1.1.10
OS10(config-dhcp-dell_2)# default-router 20.1.1.1
OS10(config-dhcp-dell_2)# end
OS10#show running-config ip dhcp
!
ip dhcp server
!
ip dhcp pool dell_1
network 10.1.1.0/24
default-router 10.1.1.1
address range 10.1.1.2 10.1.1.10

ip dhcp pool dell_2
network 20.1.1.0/24
default-router 20.1.1.1
address range 20.1.1.2 20.1.1.10
OS10# show running-configuration route

ip route 10.1.1.0/24  20.1.1.1
ip route 10.1.1.0/24  20.1.1.0

In this scenario, the remote-id value: DELL-red:90b11cf4a65d is added in the packet and sent out of the DHCPv6 relay agent. You can configure the DHCP server to allocate an IP address from a range of IP addresses based on the remote-id value received from the DHCPv6 packet. The prefix value is configured to take hostname and vrfname: DELL(DHCPv6 hostname), red(client interface's vrfname). By default, the DHCPv6 relay agent type 3 DUID (system mac - 90b11cf4a65d) is used as the remote-ID description.